Observation of a long primo vessel in a lymph vessel from the inguinal node of a rabbit.

Though primo vessels are frequently found in the lymph near the abdominal aorta of rabbit by Alcian blue dye, the reproductions are still difficult to require considerable skills and technical know-how at dissected tissue of animal species. However, in the inguinal lymph node of a rabbit we found a long-type primo vascular system (LTP) dyed with Alcian blue, from an abdominal lymph vessel to an inguinal lymph node. The length of LTP was over an average length of 9.1 cm. The average diameters of the primo and the lymph vessels were about 23.9  μ m and 242  μ m, respectively. The primo vessels were not floating but adhered to lymph vessels with fascial connective tissue. These primo vessels might be a functional integration in the lymph system.